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Unread 30-08-2007, 13:12
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Re: FIRST provided transmissions survey

Quote:
Originally Posted by JesseK View Post
Teams with non-mech. experts can put together some parts in CAD to get the basic concepts down. Unfortunately the base unmodified parts also usually make your transmission heavier than the stock KOP transmission. So it's really it becomes a time trade off for me personally, since right now I lack the knowledge (and time to learn) making custom/fancy parts in CAD for a CNC. For this year I'm simply trying to figure gearing arrangements for a simple shifting transmission. I doubt we'll have a use for it in the build season since not only is it heavier than we typically desire, we can also modify the strategy during the game to make up for lack of speed (most of the mentors here seem to be better tacticians than builders, myself included).

On another note, it's a bummer to have unit-vector based algorithms for a driver-centric holonomic drive figured out (and a possible student who's interested in learning them) only to (currently) lack the necessary mechanical expertise to make it a reality -- that's why unless things change I am still comfortable sticking with inexpensive, reliable stock transmissions -- the modified banebots did very well for us this year. Plus it allows for more time on the other important parts of the robot if we decide to do an omni drive.

Eventually, if they stick with FIRST long enough, mentors learn enough about every part of the robot that it becomes easier and easier to bring students up to speed each year, thereby advancing the complexity/reliability of everything. So in essence, it really boils down to the people you have that make up your team as to whether you should put the time into a custom transmission.
I have two suggestions here;

for the shifter you're talking about, try to make a 2-speed derivation of team 33's. they made it comlpetely on a lathe and a drill press with an x-y. There isn't that much lathework, so I'm sure you could ask around to get it done if you don't have a lathe.

"lack the necessary mechanical expertise to make it a reality"
And for this one... that's where off the shelf can be a life saver! AndyMark.biz, ifirobotics.com (heck, even robotmarketplace), etc... all have mechanical products that can be very useful.